One of the more commercially successful innovations in surgical procedures in recent years is the development of surgical stapler devices. These devices are designed to seal or simultaneously cut and seal an extended segment of tissue in a patient, vastly reducing the time and risks of such procedures. Typically, a surgical stapler comprises two stapler arms, one containing two or more lines of multiple staples (“cartridge” or “jaw”) and a second containing corresponding means to bend each of the staples into a closed position (“anvil”). For most applications, a surgical blade is included in the device to quickly sever tissue between the lines of staples. Those stapler devices employing a cutting blade are referred to as “anastomotic staplers” and those used without a cutting blade are referred to as “non-anastomotic staplers.”
In the operation of a typical anastomotic stapler, the two stapler arms are positioned around tissue to be cut and then locked firmly together. In one motion the surgeon then actuates the stapler device, which simultaneously installs and “sets” two or more lines of staples through the tissue and cuts a line down the middle of the staple lines. In this manner, the physician can quickly cut and seal up to about 8 cm of tissue at a time. This procedure is much faster than using a conventional process of cutting with scissors or a scalpel and then laboriously sealing the incision with sutures. As a result, patient care is dramatically improved by minimizing bleed time from the surgical site and significantly increasing the speed with which an operation can be completed.
For most procedures, the use of bare staples, with the staples in direct contact with the patient's tissue, is generally acceptable. The integrity of the tissue itself will normally serve to prevent the staples from tearing out of the tissue and compromising the seam before healing has occurred. However, in certain circumstances the tissue that is being sealed is too fragile to securely hold the staples in place. In these instances, the tissue will tend to rip at or near the staple lines, slowing healing and possibly leading to serious complications.
One area where fragile tissue is of particular concern is the use of stapler devices in lung tissue, and especially lung tissue that is affected by emphysema or similar condition. Diseased lung tissue is very fragile and, in extreme cases, will easily tear through unprotected staple lines. With the growing use of surgical staplers in operations on diseased lung tissues such as bullectomies and volume reduction procedures, it has become increasingly important to develop some reliable means to protect fragile tissue from tissue tears due to surgical staples or surgical stapling procedures.
A surgical stapler reinforcement material is disclosed in U.S. Pat. No. 5,441,193 to Gravner. A resilient strip of material is pre-attached to a stapler jaw and/or anvil. The surgical staples are fired and set through the tissue and resilient material which strengthens and reinforces the staples. The resilient material can be pre-attached to the stapler by the use of adhesives or by mechanical means such as grooves, slots or projections. Once the staples are fired, the reinforcement material is released from the stapler jaw and/or anvil. Since the reinforcement material of Gravner is pre-attached to the stapler, it is only suited for those staplers specifically designed to receive the configuration of Gravner. Due to the integral nature of the stapler and the reinforcement material, no carrier facilitating the loading of the reinforcement material onto the stapler is required.
In U.S. Pat. Nos. 5,503,638, 5,575,803 and 5,549,628 to Cooper et al., an alternate configuration of a staple reinforcement material is disclosed. In these patents, a disposable sleeve is attached to the reinforcement material. The sleeve is formed into a three-sided “U” shape, which is sized to slip-fit over a stapler jaw or anvil. The fourth side of the sleeve is comprised of the reinforcement material which contacts the active surface of stapler jaw or anvil. The reinforcement material is releasibly attached to the disposable sleeve, for example by a suture. After the staples are fired, the reinforcement material is released from the disposable sleeve by unthreading the suture. The disposable sleeve must then be removed and discarded. Such a reinforcement material is more suited for open surgical procedures. In laparoscopic procedures, the sleeve surrounding the stapler jaw and anvil can interfere with the trocar. This requires the use of oversized trocars and removal of the suture attachment through the trocar. The disposable sleeve must also be captured and withdrawn through the trocar.
Staple line reinforcement devices are commercially available from W. L. Gore & Associates, Inc., Flagstaff, Ariz., under the trademark SEAMGUARD®. Such staple line reinforcement devices are described in U.S. Pat. Nos. 5,702,409 and 5,810,855 to Rayburn et al. These devices comprise a material formed into a sleeve, which is sized to slip-fit over a stapler jaw or anvil. The sleeve incorporates tear lines or other means to allow easy separation of the disposable portions of the device, from the portions secured by the fired staples. Retrieval means, such as a suture, capture and allow retrieval of the disposable portions of the device. In laparoscopic procedures, there are concerns similar to those discussed in Cooper.
An alternate staple line reinforcement device is commercially available from Bio-Vascular, Inc., Saint Paul, Minn. under the trademark PERI-STRIPSDRY™. U.S. Pat. No. 5,752,965 to Francis et al. describes such a reinforcement device and a carrier used to present and load the device onto a stapler. This reinforcement material, comprising dried and treated bovine pericardium, is in the form of a strip sized to cover the desired part of the stapler. One or two of these pericardial strips are releasibly attached to the carrier. Just prior to use, an adhesive gel is applied to the pericardial strips. The gel softens the strips and acts as an adhesive to allow temporary attachment to the stapler. The stapler is then self-aligned to the carrier, the jaws are closed upon the pericardial strips, and the gel adheres the strips to the stapler jaws. Unlike the slip-fit tubes of other reinforcement devices, the pericardial strips do not surround the stapler jaws. In order to provide for application of the strips, the Francis et al. patent teaches use of an apparatus having multiple deep guide channels to self-direct the surgical fastener into contact with the reinforcement material, and integral pressure equalization means in the form of resilient foam or similar material attached to the receiving area of the applicator card to aid in establishing a uniform adherence of the reinforcement strips to the surgical fastener.
There are a number of serious deficiencies with the Francis et al. apparatus. First, the use of bovine pericardium material is undesirable since this material requires preparation prior to use and must be kept moist to prevent embrittling and cracking when the staples are fired. Thus staples must be fired soon after mounting of the reinforcement material, limiting the ability to prepare multiple staplers with reinforcement devices prior to use. The implantation of bovine material also raises concerns associated with bovine maladies that can be transmitted to humans, such as Creutzfelt-Jakob Disease (CJD) or Bovine Spongiform Encephalopathy (BSE). Second, the carrier apparatus of Francis et al. may function adequately well for its intended purpose, but it is believed to be overly bulky in design due to the requirement for deep perpendicularly mounted guide channels. Additionally, the apparatus of Francis et al. does not optimize material adherence to the surgical stapler. For instance, the method of attachment of the reinforcement material to the stapler arms is difficult to engineer among a variety of staple arm designs—thus requiring use of an integral layer of resilient foam to attempt to compensate for inaccurate sizing. Not only does the pressure equalizing foam provide less than optimal adherence, but due to the fact that Francis et al. teach that the foam is removed along with the reinforcement material upon application, additional steps are required for the surgical staff to remove and discard the foam prior to the insertion of the stapler into the patient.
An improved staple line reinforcement device would have desirable features that allow lower profile insertion and would not require the removal of excess reinforcement material following deployment. In addition, it would be desirable to provide a reinforcement material that provides effective and simple “one-step” attachment to a stapler with minimal pre- and post-attachment requirements.